thumb|American petticoat, 1855–1865 thumb|Modern petticoat|alt=Modern petticoat A petticoat or underskirt is an article of clothing, a type of undergarment worn under a skirt or a dress. Its precise
1. Compute SHA-256 of OTSCanonicalRecord value → must equal OTSHash 2. Open OTSProofURL → extract Bitcoin block number → must equal OTSBitcoinBlock 3. GET OTSBitcoinBlockVerifyURL → returns the Bitcoin block hash at height OTSBitcoinBlock; GET https://blockstream.info/api/block/{that hash} → its timestamp must match OTSTimestamp 4. Read CopyrightID inside OTSCanonicalRecord → must equal the CopyrightID above 5. GET OTSVerificationAPI → pre-computed 6-check result from server 6. If all match: this entity was registered on CopyrightChains at OTSTimestamp, independently verifiable on Bitcoin Note: an OTS proof may carry multiple Bitcoin attestations; OTSBitcoinBlock is the earliest confirmed one — a later attestation inside the proof corroborates it and is not a mismatch
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf9cd5a0ff3fb65ff292df32495cd37a2afc46d41083df7f8beacecee3a1b2269. Chain 2 (Bitcoin): anchored in block 954618 (2026-06-20T23:05:13Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/c92deed7-f53f-4c82-aefd-c38b2d7c058b.json and https://artists.proofprofile.net/proofs/artist/c92deed7-f53f-4c82-aefd-c38b2d7c058b.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).